CN117501587A - Motor, blower and air conditioner - Google Patents

Abstract

The motor has a rotor and a stator. The rotor has an annular rotor core centered on an axis and a permanent magnet attached to the rotor core. The permanent magnets constitute magnet poles, and a part of the rotor core constitutes virtual poles. The stator includes a stator core surrounding the rotor core from a radial outer side centered on the axis, and a coil wound around the stator core. The stator core has a slot for receiving the coil. The stator core has a1 st core portion located at the center in the direction of the axis of the stator core and a2 nd core portion located at the end in the direction of the axis of the stator core. The area of the groove in the 2 nd core portion is larger than the area of the groove in the 1 st core portion.

Description

Motor, blower and air conditioner

Technical Field

The present disclosure relates to a motor, a blower, and an air conditioning device.

Background

In recent years, motors having commutated pole type rotors have been developed. In the commutated pole rotor, a permanent magnet attached to a rotor core constitutes a magnet pole, and a part of the rotor core constitutes a virtual pole (see patent document 1, for example).

Prior art literature

Patent literature

Patent document 1: international publication WO2018/037449 (see FIG. 9)

Disclosure of Invention

Problems to be solved by the invention

The magnetic flux from the rotor is interlinked with the coils of the stator of the motor, thereby generating a driving force. Here, since the permanent magnets are not present in the virtual magnetic poles of the rotor, the magnetic flux density distribution in the virtual magnetic poles is liable to be shifted due to the influence of the stator magnetic field. When such a shift in the magnetic flux density distribution occurs, the core loss of the stator core increases, and the temperature of the stator core tends to rise.

The present disclosure has been made to solve the above-described problems, and an object thereof is to suppress a temperature rise of a stator core in a motor using a commutated pole rotor.

Means for solving the problems

The motor of the present disclosure has a rotor and a stator. The rotor has an annular rotor core centered on an axis and a permanent magnet attached to the rotor core. The permanent magnets constitute magnet poles, and a part of the rotor core constitutes virtual poles. The stator includes a stator core surrounding the rotor core from a radial outer side centered on the axis, and a coil wound around the stator core. The stator core has a slot for receiving the coil. The stator core has a1 st core portion located at the center in the direction of the axis of the stator core and a2 nd core portion located at the end in the direction of the axis of the stator core. The area of the groove in the 2 nd core portion is larger than the area of the groove in the 1 st core portion.

Effects of the invention

According to the present disclosure, the area of the slot in the 1 st core portion of the stator core is larger than the area of the slot in the 2 nd core portion, and therefore, the coil can be wound in such a manner that the interval between the coil and the stator core is as narrow as possible. As a result, heat of the stator core can be radiated via the coil, and a temperature rise of the stator core can be suppressed.

Drawings

Fig. 1 is a longitudinal sectional view showing a motor according to embodiment 1.

Fig. 2 is a cross-sectional view showing the motor of embodiment 1.

Fig. 3 is a cross-sectional view showing the rotor core and the permanent magnet of embodiment 1.

Fig. 4 is a plan view showing the 1 st core portion of the stator core according to embodiment 1.

Fig. 5 is a plan view showing the 2 nd core portion of the stator core of embodiment 1.

Fig. 6 is a perspective view (a) showing the stator core of embodiment 1, a perspective view (B) showing the stator core and the insulator, and a perspective view (C) showing the stator core, the insulator, and the insulating film.

Fig. 7 is a cross-sectional view (a) showing the tooth and the insulating portion of embodiment 1 and a cross-sectional view (B) showing the tooth and the insulating portion of the comparative example.

Fig. 8 is a schematic diagram (a) showing a state in which a coil is wound around a tooth according to embodiment 1 and a schematic diagram (B) showing a state in which a coil is wound around a tooth according to a comparative example.

Fig. 9 is a schematic diagram showing a winding method of the coil according to embodiment 1 with respect to teeth.

Fig. 10 is a cross-sectional view showing a wound state of the coil of embodiment 1 with respect to the teeth.

Fig. 11 is a side view showing a state in which the coil of embodiment 1 is wound around the teeth.

Fig. 12 is a diagram (a) and (B) showing the arrangement of coil wires in each layer of the coil of embodiment 1.

Fig. 13 is a cross-sectional view showing a rotor of the comparative example.

Fig. 14 is a cross-sectional view showing the stator core of embodiment 2.

Fig. 15 is a diagram (a) and (B) showing a state in which the stator core is linearly expanded in embodiment 2.

Fig. 16 is a diagram (a) showing an air conditioner to which the motor according to each embodiment can be applied, and a cross-sectional view (B) showing an outdoor unit of the air conditioner.

Detailed Description

Embodiment 1

< Structure of Motor 2 >

Fig. 1 is a longitudinal sectional view showing a motor 2 in embodiment 1. The motor 2 is used for, for example, a blower of an air conditioner, and is driven by an inverter. The motor 2 is an IPM (permanent magnet embedded) motor in which a permanent magnet 55 is embedded in a rotor 5.

The motor 2 has a shaft 6, a rotor 5 mounted to the shaft 6, and a molded stator 3 surrounding the rotor 5. The molded stator 3 has an annular stator 1 surrounding a rotor 5 and a molded resin portion 4 covering the stator 1. The shaft 6 is a rotation shaft of the rotor 5.

In the following description, the direction of the axis Ax, which is the central axis of the shaft 6, will be referred to as the "axial direction". The circumferential direction around the axis Ax is referred to as a "circumferential direction", and the radial direction around the axis Ax is referred to as a "radial direction". A cross-sectional view of a plane perpendicular to the axis Ax is referred to as a "cross-sectional view", and a cross-sectional view of a plane parallel to the axis Ax is referred to as a "longitudinal cross-sectional view".

The shaft 6 protrudes leftward in fig. 1 from the molded stator 3, and an impeller 511 of a blower, for example, is mounted to a mounting portion 61 formed at the protruding portion thereof (fig. 16 (a)). Therefore, the protruding side (left side in fig. 1) of the shaft 6 is referred to as "load side", and the opposite side (right side in fig. 1) is referred to as "load opposite side".

< Structure of molded stator 3 >

As described above, the molded stator 3 has the stator 1 and the molded resin portion 4. The molding resin portion 4 is formed of a thermosetting resin such as an unsaturated polyester resin or an epoxy resin. The unsaturated polyester resin is, for example, bulk Molding Compound (BMC).

The molded resin portion 4 covers the radial outside and the load opposite side of the stator 1. The molded resin portion 4 has an opening 41 on the load side and a bearing support 42 on the opposite load side. The rotor 5 is inserted into the stator 1 through the opening 41.

A bracket 65 made of metal is attached to the opening 41 of the molded resin part 4. The 1 st bearing 62 supporting the shaft 6 is held by the bracket 65. The waterproof cap 64 is attached to the shaft 6 so as to cover the outer side of the bracket 65. The 2 nd bearing 63 supporting the shaft 6 is held in the bearing support portion 42 of the molded resin portion 4.

A circuit board 45 is disposed on the opposite side of the stator 1 to the load. The circuit substrate 45 is covered with the mold resin portion 4. A drive circuit 46, a magnetic sensor, and the like necessary for driving the motor 2 are mounted on the circuit board 45.

Further, leads 47 electrically connected to the coils 30 of the stator 1 are wired to the circuit board 45. The lead 47 is led out to the outside from a lead-out member 48 provided at the outer peripheral portion of the molded resin part 4.

The heat radiating member 44 is preferably provided on the opposite side of the circuit board 45 from the stator 1. The heat sink 44 is made of a metal such as aluminum. The side of the heat radiating member 44 opposite to the stator 1 is exposed from the mold resin portion 4, and the other portions are covered with the mold resin portion 4.

The heat radiating member 44 may be a heat radiator having ribs at a portion exposed from the molded resin portion 4, or may be a plate-shaped heat radiating plate. The heat radiating member 44 has a function of radiating heat generated in the stator 1 and the circuit substrate 45 to the outside.

In addition, the motor 2 is not limited to the structure having the molded resin portion 4. For example, the stator 1 of the motor 2 may be fixed to the inside of a cylindrical case containing iron (Fe) as a main component by press fitting or the like.

Fig. 2 is a cross-sectional view showing the stator 1 and the rotor 5 of the motor 2. In fig. 2, the molded resin portion 4 is not shown. The stator 1 includes a stator core 10 surrounding a rotor core 50 from the radial outside through an air gap G, an insulating portion 20 provided in the stator core 10, and a coil 30 wound around the stator core 10 through the insulating portion 20.

The stator core 10 is obtained by stacking a plurality of stacked elements in the axial direction and fixing the stacked elements by caulking, welding, bonding, or the like. The laminated element is a thin plate having magnetism, more specifically, a steel plate containing iron as a main component. More specifically, the lamination element is an electromagnetic steel sheet. The thickness of the laminated element is, for example, 0.2mm to 0.5mm.

The stator core 10 includes a yoke 11 extending in an annular shape centering on the axis Ax, and a plurality of teeth 12 extending radially inward from the yoke 11. Here, the number of teeth 12 is 12, but is not limited thereto. A tip 12e facing the rotor 5 is formed at the tip of the tooth 12. The circumferential width of the tooth top 12e is wider than the rest of the tooth 12.

The yoke 11 is formed with 12 caulking portions 10c, and each tooth 12 is also formed with a caulking portion 10d. The caulking portions 10c and 10d are portions for fixing the lamination elements of the stator core 10 to each other. The caulking portions 10c, 10d are located on a straight line passing through the center of each tooth 12 in the radial direction. However, the number and arrangement of the caulking portions 10c and 10d are arbitrary, and the stacked elements may be fixed by a method other than caulking.

Grooves 13 are formed between circumferentially adjacent teeth 12. The number of grooves 13 is the same as the number of teeth 12. The coil 30 is wound around the tooth 12 via the insulating portion 20 and is accommodated in the slot 13. The coil 30 has a conductor formed of a copper wire or an aluminum wire and an insulating film surrounding the conductor.

The winding method of the coil 30 has concentrated winding and distributed winding, where concentrated winding is used. In particular, instead of winding the coil 30 across the plurality of teeth 12, the winding is performed tooth by tooth 12. This winding method is called salient pole concentrated winding.

The insulating portion 20 includes an insulator 21 (fig. 1) disposed on an axial end surface of the stator core 10 and an insulating film 22 disposed on an inner surface of the slot 13. In addition, a part of the molded resin portion 4 shown in fig. 1 enters the groove 13, covering the coil 30 together with the insulating film 22.

< Structure of rotor 5 >

As shown in fig. 2, the rotor 5 includes a shaft 6, a rotor core 50 surrounding the shaft 6 from the radially outer side, and a plurality of permanent magnets 55 embedded in the rotor core 50. Here, the number of permanent magnets 55 is 5.

Fig. 3 is a cross-sectional view showing the rotor core 50 and the permanent magnets 55. The rotor core 50 is an annular member centered on the axis Ax. The rotor core 50 has an outer periphery 50a and an inner periphery 50b, and the inner periphery 50b faces the shaft 6 (fig. 2).

The rotor core 50 is obtained by stacking a plurality of stacked elements in the axial direction and fixing the stacked elements by caulking, welding, bonding, or the like. The laminated element is a thin plate having magnetism, more specifically, a steel plate containing iron as a main component. More specifically, the lamination element is an electromagnetic steel sheet. The thickness of the laminated element is, for example, 0.2mm to 0.5mm.

The rotor core 50 has a plurality of magnet insertion holes 51 in the circumferential direction. The magnet insertion holes 51 are equally spaced in the circumferential direction and are arranged equidistantly with respect to the axis Ax. Here, the number of the magnet insertion holes 51 is 5. The magnet insertion hole 51 is formed along the outer periphery 50a of the rotor core 50, and penetrates the rotor core 50 in the axial direction.

Permanent magnets 55 are inserted into the respective magnet insertion holes 51. The permanent magnet 55 has a flat plate shape and a rectangular cross section on a surface perpendicular to the axial direction. The permanent magnet 55 is a rare earth magnet, more specifically, a neodymium magnet containing neodymium (Nd), iron, and boron (B), or a samarium magnet containing samarium (Sm) and cobalt (Co). In addition, ferrite magnets may be used instead of rare earth magnets.

Magnetic flux barriers 52 as gaps are formed at both ends of the magnet insertion hole 51 in the circumferential direction. A thin wall portion is formed between the flux barrier 52 and the outer periphery 50a of the rotor core 50. The thickness of the thin portion is set to be the same as the thickness of the laminated element, for example, to suppress short-circuiting of magnetic fluxes between the adjacent permanent magnets 55.

The permanent magnets 55 are arranged such that the magnetic pole faces of the same polarity face the outer peripheral side of the rotor core 50. In the rotor core 50, magnetic poles having a polarity opposite to that of the permanent magnets 55 are formed in regions between the permanent magnets 55 adjacent in the circumferential direction.

Therefore, in the rotor 5, the magnet poles P1 constituted by the permanent magnets 55 and the virtual poles P2 constituted by a part of the rotor core 50 are alternately arranged in the circumferential direction. This structure is called a commutating pole type. Here, the magnet pole P1 is the S pole, and the virtual pole P2 is the N pole, but the opposite may be also adopted. In the circumferential direction, an inter-pole portion M is formed between the magnetic poles P1, P2.

The rotor 5 has 5 magnet poles P1 and 5 virtual poles P2. That is, the number of poles of the rotor 5 is 10. The 10 magnetic poles P1 and P2 of the rotor 5 are arranged at equal angular intervals in the circumferential direction so that the pole pitch is 36 degrees. The number of poles of the rotor 5 is 10 here, but the number of poles may be 4 or more. That is, the number of the magnet poles P1 may be 2 or more.

Hereinafter, the magnet pole P1 and the virtual pole P2 will be simply referred to as "poles" unless a special distinction is required. The center of the magnet pole P1 in the circumferential direction is the pole center. Similarly, the center of the virtual magnetic pole P2 in the circumferential direction is the pole center.

The outer periphery 50a of the rotor core 50 has a so-called flower shape in a cross section perpendicular to the axial direction. In other words, the outer periphery 50a of the rotor core 50 extends such that the radius of the rotor core 50 is largest at the center of each pole of the magnetic poles P1, P2 and smallest at the inter-pole portion M. The outer periphery 50a of the rotor core 50 is not limited to a flower shape, and may have a circular shape.

The virtual magnetic pole P2 is preferably formed with a slit group 53. The slit group 53 uniformly distributes the magnetic flux concentrated at the pole center of the virtual magnetic pole P2 in the circumferential direction. The slit group 53 has, for example, 2 slits 53a arranged at the center of the pole, and 2 slits 53b arranged on both sides thereof.

Both slits 53a, 53b are radially longer. Further, the opening area of the slit 53b is larger than the opening area of the slit 53 a. However, the number, arrangement, and shape of the respective slits of the slit group 53 are arbitrary.

In the rotor core 50, a hole 54 is formed radially inward of the magnet insertion hole 51. The hole 54 guides the magnetic flux coming out from the pole surface on the inner side in the radial direction of the permanent magnet 55 or the magnetic flux flowing into the pole surface uniformly in the circumferential direction.

A protruding portion 50d protruding in an arc shape along each hole 54 is formed on the inner periphery 50b of the rotor core 50. The inner periphery 50b of the rotor core 50 is circular with the axis Ax as the center, except for the protruding portion 50d. In addition, the hole 54 and the protruding portion 50d do not have to be provided in the rotor core 50.

In the rotor core 50, caulking portions 50c are formed radially inward of each slit group 53. The caulking portion 50c is a portion for fixing the lamination elements of the rotor core 50 to each other. However, the number and arrangement of the caulking portions 50c are arbitrary, and the stacked elements may be fixed by a method other than caulking.

As shown in fig. 2, a coupling portion 56 is provided between the shaft 6 and the rotor core 50. The coupling portion 56 couples the shaft 6 and the rotor core 50, and is non-magnetic.

The connection portion 56 is formed of a nonmagnetic resin such as BMC, polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyethylene terephthalate (PET), or the like. The connection portion 56 may be formed of a nonmagnetic metal such as austenitic stainless steel or aluminum.

The commutating pole rotor 5 has a characteristic that magnetic flux passing through the virtual magnetic pole P2 easily flows to the shaft 6, but by providing a non-magnetic coupling portion 56 between the rotor core 50 and the shaft 6, leakage of magnetic flux from the rotor core 50 to the shaft 6 is suppressed. The connecting portion 56 may have a hollow portion or a rib.

As shown in fig. 1, the connecting portions 56 also cover both end surfaces in the axial direction of the rotor core 50. It is preferable that a part of the coupling portion 56 also enters the magnet insertion hole 51 of the rotor core 50. A part of the coupling portion 56 enters the magnet insertion hole 51, thereby suppressing positional displacement of the permanent magnet 55 in the magnet insertion hole 51.

The sensor magnet 66 is disposed on the opposite side of the rotor core 50 from the load. The sensor magnet 66 is an annular permanent magnet centered on the axis Ax, and is held by the coupling portion 56. The magnetic field of the sensor magnet 66 is detected by the magnetic sensor of the circuit substrate 45, thereby detecting the rotational position of the rotor 5. The sensor magnet 66 is sometimes not provided in the rotor 5.

In addition, the axial length of the rotor core 50 is preferably longer than the axial length of the stator core 10. With this configuration, the magnetic flux from the rotor 5 also flows sufficiently into the axial end face of the stator core 10, and therefore the motor efficiency improves.

Here, the coupling portion 56 is provided between the rotor core 50 and the shaft 6, but the shaft 6 may be fixed to the inner periphery 50b of the rotor core 50 without providing the coupling portion 56. The fixing method comprises the steps of pressing in, hot press fit, chiseling and the like. In this case, in order to suppress leakage of magnetic flux from the rotor core 50 toward the shaft 6, the shaft 6 is preferably made of a nonmagnetic material such as austenitic stainless steel or aluminum.

< Structure for winding coil 30 around stator core 10 >

As described with reference to fig. 2, the stator core 10 includes an annular yoke 11 and teeth 12 extending radially inward from the yoke 11. Slots 13 for receiving coils 30 are formed between adjacent teeth 12. A slot opening 14 (fig. 4) serving as an inlet for inserting the coil 30 into the slot 13 is formed radially inside the slot 13.

The stator core 10 further includes a1 st core portion 10A (fig. 4) located at the center in the axial direction of the stator core 10 and a2 nd core portion 10B (fig. 5) located at both end portions in the axial direction. The areas of the slots 13 are different between the 1 st core portion 10A and the 2 nd core portion 10B.

Fig. 4 is a plan view showing the 1 st core portion 10A of the stator core 10. The tooth 12 of the 1 st core portion 10A has side surfaces 12b at both ends in the circumferential direction thereof. The side 12b faces the groove 13. The yoke 11 of the 1 st core portion 10A has an outer periphery 11a and an inner periphery 11b. The inner periphery 11b faces the groove 13.

The circumferential width W1 of the tooth 12 of the 1 st core portion 10A is defined by the circumferential distance of the 2 side surfaces 12b of the tooth 12. The radial width T1 of the yoke 11 of the 1 st core portion 10A is defined by the radial distance between the outer periphery 11a and the inner periphery 11b of the yoke 11.

Fig. 5 is a plan view showing the 2 nd core portion 10B of the stator core 10. The tooth 12 of the 2 nd core portion 10B has side surfaces 12c at both ends in the circumferential direction thereof. The side 12c faces the groove 13. The yoke 11 of the 2 nd core portion 10B has an outer periphery 11a and an inner periphery 11c. The inner periphery 11c faces the groove 13.

The circumferential width W2 of the tooth 12 of the 2 nd core portion 10B is defined by the circumferential distance of the 2 side surfaces 12c of the tooth 12. The radial width T2 of the yoke 11 of the 2 nd core portion 10B is defined by the radial distance between the outer periphery 11a and the inner periphery 11c of the yoke 11.

The width W2 of the tooth 12 of the 2 nd core portion 10B is narrower than the width W1 of the tooth 12 of the 1 st core portion 10A (W1 > W2). Further, the width T2 of the yoke 11 of the 2 nd core portion 10B is narrower than the width T1 of the yoke 11 of the 1 st core portion 10A (T1 > T2). The outer periphery 11a of the yoke 11 is located at the same radial position in the 1 st core portion 10A and the 2 nd core portion 10B.

With this configuration, the area A2 of the groove 13 in the 2 nd core portion 10B is larger than the area A1 of the groove 13 in the 1 st core portion 10A (A1 < A2).

Here, the widths W1, W2 of the teeth 12 satisfy W1> W2, and the widths T1, T2 of the yoke 11 satisfy T1> T2, but at least the widths W1, W2 of the teeth 12 may satisfy W1> W2.

In other words, the side surface 12c (fig. 5) of the tooth 12 of the 2 nd core portion 10B may be located at a position shifted inward in the width direction of the tooth 12 with respect to the side surface 12B (fig. 4) of the tooth 12 of the 1 st core portion 10A.

Further, it is preferable that the facing surface 12g (fig. 5) which is the surface on the groove 13 side of the tooth crest 12e of the 2 nd core portion 10B is formed at a position shifted radially inward with respect to the facing surface 12f (fig. 4) of the tooth crest 12e of the 1 st core portion 10A.

Fig. 6 (a) is a perspective view showing a portion including 1 tooth 12 of the stator core 10 cut along a plane passing through the yoke 11. A step portion is formed between the side surface 12B of the tooth 12 of the 1 st core portion 10A and the side surface 12c of the tooth 12 of the 2 nd core portion 10B.

A step portion is also formed between the inner periphery 11B of the yoke 11 of the 1 st core portion 10A and the inner periphery 11c of the yoke 11 of the 2 nd core portion 10B. A step is also formed between the facing surface 12f of the tooth top 12e of the 1 st core portion 10A and the facing surface 12g of the tooth top 12e of the 2 nd core portion 10B.

The insulator 21 described later engages with these stepped portions formed in the stator core 10.

Fig. 6 (B) is a perspective view showing a state in which the insulator 21 is attached to the stator core 10. The insulators 21 are attached to the 2 nd core portion 10B, which is the axial both ends of the stator core 10 (fig. 6 a). The insulator 21 is made of, for example, a resin such as PBT, PPS, LCP, PET.

Each insulator 21 has a wall portion 21a located on the yoke 11, a body portion 21b located on the tooth 12, and a flange portion 21c located on the tooth tip portion 12e of the tooth 12. The flange portion 21c and the wall portion 21a are opposed to each other in the radial direction through the body portion 21b.

The coil 30 is wound around the main body 21b. The wall portion 21a and the flange portion 21c guide the coil 30 wound around the main body portion 21b from both sides in the radial direction. The wall portion 21a and the flange portion 21c may be provided with a step portion 21d for positioning the coil 30 wound around the body portion 21b.

Fig. 6 (C) is a perspective view showing a state in which the insulator 21 and the insulating film 22 are attached to the stator core 10. An insulating film 22 is attached to the inner surface of the slot 13 of the 2 nd core portion 10B.

The insulating film 22 covers the inner periphery 11B of the yoke 11 of the 2 nd core portion 10B, the side surface 12B of the tooth 12, and the facing surface 12f of the tooth tip portion 12e (both in fig. 6 (B)). The insulating film 22 is made of, for example, a resin such as PET. The thickness of the insulating film 22 is, for example, 0.35 to 0.4mm.

The insulator 21 and the insulating film 22 electrically insulate the stator core 10 and the coil 30. The insulator 21 and the insulating film 22 are collectively referred to as an insulating portion 20.

Fig. 7 (a) is a cross-sectional view of the tooth 12 and the insulating portion 20 of embodiment 1, the cross-sectional view being perpendicular to the extending direction of the tooth 12. As shown in fig. 7 (a), the side surface 12c of the tooth 12 of the 2 nd core portion 10B is located on the inner side in the width direction of the tooth 12 than the side surface 12B of the tooth 12 of the 1 st core portion 10A.

Therefore, stepped portions are formed on both sides of the teeth 12 of the 2 nd core portion 10B. The main body 21b of the insulator 21 is attached so as to cover the end face 12a in the axial direction of the tooth 12, and is fitted to the stepped portion of the tooth 12. In other words, the insulator 21 has an engagement portion 21h that engages with the stepped portion of the tooth 12.

The tooth 12 has a corner C1 between the end face 12a and the side face 12b, and a corner C2 between the stepped face and the side face 12C in a cross section perpendicular to the extending direction of the tooth 12. The insulator 21 has a corner 21e of a curved shape covering these corners C1, C2. The corner 21e extends so as to cover the corners C1 and C2, and therefore, the radius of curvature of the corner 21e can be increased.

Like the engaging portion 21h of the main body portion 21b of the insulator 21, the wall portion 21a of the insulator 21 has an engaging portion 21i that engages with the stepped portion of the yoke 11 (fig. 6 (C)), and the flange portion 21C has an engaging portion 21j that engages with the stepped portion of the tooth top portion 12e (fig. 6 (C)).

Fig. 7 (B) is a cross-sectional view of the face of the tooth 112 and the insulator 120 of the comparative example, which face is perpendicular to the extending direction of the tooth 112. As shown in fig. 7 (B), the teeth 112 of the comparative example have a rectangular cross section. The insulator 120 is installed in such a manner as to surround the teeth 112 from both circumferential and axial sides.

In comparative example 1, the cross section of the tooth 112 is rectangular, and therefore, the radius of curvature of the corner 121 of the insulator 120 is relatively small. This is because, when the radius of curvature of the corner 121 of the insulator 120 is increased, the distance d between the corner 121 of the insulator 120 and the corner of the tooth 112 becomes short, and it is difficult to secure insulation.

Fig. 8 (a) is a schematic diagram showing a state in which coil 30 is wound around tooth 12 in embodiment 1. As described with reference to fig. 7 (a), since the corner 21e of the insulator 21 has a large radius of curvature, the coil 30 can be wound in close contact with the insulator 21 and the insulating film 22. Therefore, the interval between the teeth 12 and the coil 30 becomes narrow, and heat transfer between the teeth 12 and the coil 30 via the insulating film 22 can be performed.

Fig. 8 (B) is a schematic diagram showing a state in which the coil 30 is wound around the teeth 112 of the comparative example. As described with reference to fig. 7 (B), since the radius of curvature of the corner 121 of the insulator 120 is small, when the coil 30 is wound around the insulator 120, a gap B is generated between the coil 30 and the side surface of the insulator 120. Due to this gap B, heat transfer between the teeth 112 and the coil 30 is hindered.

As described above, in embodiment 1, regarding the width of the teeth 12 of the stator core 10, the step portions are formed at both axial end portions of the teeth 12 by being narrower in the 2 nd core portion 10B than in the 1 st core portion 10A. Therefore, the coil 30 can be wound in close contact with the insulating portion 20 surrounding the teeth 12. Thereby, heat of the stator core 10 can be transferred to the coil 30 via the insulating film 22.

Next, a structure for disposing the coils 30 in the slots 13 at a higher density will be described. Fig. 9 is a schematic diagram showing a winding method of the coil 30 of embodiment 1. Fig. 9 is a view of the insulator 21 as seen from one side in the axial direction. In fig. 9, the circumferential direction is indicated by an arrow C. As described above, the coil 30 is wound around the main body 21b of the insulator 21.

As indicated by an arrow B1, the 1 st layer of the coil 30 is wound from the flange portion 21c of the insulator 21 toward the wall portion 21 a. Further, as indicated by an arrow B2, the 2 nd layer of the coil 30 is wound from the wall portion 21a of the insulator 21 toward the flange portion 21c. The directions of the arrows B1 and B2 may be reversed.

Fig. 10 is a cross-sectional view of a surface perpendicular to the axial direction showing a winding mode of the coil 30 of embodiment 1. In fig. 10, the circumferential direction is indicated by an arrow C, and the radial direction is indicated by an arrow R. The 1 st, 2 nd, 3 rd and 4 th layers of the coil 30 are denoted by the reference numerals L1, L2, L3 and L4, respectively.

The coil wires of the respective layers of the coil 30 are arranged without gaps in the radial direction. That is, the coil lines 31 constituting the 1 st layer L1 extend parallel to each other, and the coil lines 32 constituting the 2 nd layer L2 extend parallel to each other.

However, the coil wire 32 of the layer 2L 2 extends obliquely with respect to the coil wire 31 of the layer 1L 1 on one end face 12a of the both end faces 12a in the axial direction of the tooth 12. That is, the intersection point a at which the coil wire 31 of the 1 st layer L1 and the coil wire 32 of the 2 nd layer L2 intersect is located on the end face 12a of the tooth 12.

The coil lines of the odd layers (for example, the 3 rd layer L3) of the coil 30 extend in parallel with the coil lines 31 of the 1 st layer L1. The coil lines of the even layer (e.g., layer 4L 4) of the coil 30 extend parallel to the coil lines 32 of layer 2L 2. Therefore, when N is a natural number, the coil wire of the N-th layer and the coil wire of the n+1-th layer intersect on the end face 12a of the tooth 12.

Fig. 11 is a side view of the coil 30 from the slot 13 side. In the slot 13, coil lines of the respective layers of the coil 30 extend in a direction (indicated by an arrow Z) parallel to the axis Ax. That is, all coil lines of the coil 30 extend in parallel in the slot 13, and no crossing point exists.

Fig. 12 (a) is a schematic diagram showing a stacked state of the coils 30 located in the slots 13. In the slot 13, the coils 30 are stacked such that 1 coil wire of the n+1th layer is in line contact with 2 coils of the N-th layer. For example, 1 coil wire 33 of layer 3L 3 is in contact with 2 coil wires 32 of layer 2L 2.

In other words, the coils 30 are stacked such that the centers of the 1 st coil wire of the n+1 th layer and the centers of the 2 nd coil wires of the N-th layer constitute a regular triangle. For example, the center of 1 coil wire 33 of layer 3L 3 and the center of 2 coil wires 32 of layer 2L 2 constitute a regular triangle.

This winding method is called orderly winding. In the orderly winding, the gaps between the coil wires constituting the coils 30 are small, and the coils 30 are arranged at the highest density. Further, by winding the coils 30 in a regular arrangement, the space factor of the slot 13 is increased.

On the other hand, at the intersection a (fig. 10) described above, as shown in fig. 12 (B), 1 coil line of the n+1th layer is overlapped on 1 coil line of the N-th layer. For example, 1 coil wire 33 of layer 3L 3 is in contact with only 1 of the coil wires 32 of layer 2L 2. At the intersection a, the gap of the coil wire constituting the coil 30 is wide, and the arrangement density of the coil 30 is reduced.

In general, if the coil 30 is wound such that 1 coil wire of the n+1-th layer of the coil 30 contacts 2 coil wires of the N-th layer (refer to fig. 12 (a)) except for a part such as the intersection point a, it can be said that orderly winding is performed.

That is, if the number of portions of the coil 30 as a whole that are wound so that the 1 st coil wire of the n+1 layer contacts the 2 nd coil wires of the N layer is large, it can be said that the coils are wound in a regular arrangement.

As described above, the tooth 12 has the end face 12a and the side face 12b, and the axial length of the side face 12b is longer than the circumferential width of the end face 12 a. Therefore, the end face 12a of the tooth 12 is also referred to as a short side, and the side face 12b is also referred to as a long side.

The winding manner in which the intersection point a of the coil 30 is located on the end face 12a of the tooth 12 is referred to as short-side cross winding. In contrast, the winding method in which the intersection point a of the coil 30 is located on the side face 12b of the tooth 12 is called long-side cross winding. The winding method of the coil 30 of embodiment 1 is short-side cross winding.

As described with reference to fig. 12 (a) and (B), the arrangement density of the coils 30 is reduced at the intersection a, and therefore, by disposing the intersection a on the end face 12a of the tooth 12, the arrangement density of the coils 30 in the groove 13 can be increased.

< action >

Next, the operation of the embodiment will be described. First, the non-commutated pole type rotor 9 of the comparative example will be described.

Fig. 13 is a cross-sectional view showing the non-commutated pole rotor 9 of the comparative example. The rotor core 90 of the rotor 9 has a plurality of magnet insertion holes 91 in the circumferential direction, and permanent magnets 95 are disposed in the magnet insertion holes 91. A shaft hole 93 is formed in the radial center of the rotor core 90, and the shaft 6 is fixed to the shaft hole 93.

The permanent magnets 95 adjacent in the circumferential direction have magnetic pole faces of opposite polarities on the outer circumferential side. Therefore, all the magnetic poles of the rotor 9 are formed by the permanent magnets 95. The number of permanent magnets 95 of the rotor 9 is 10, and therefore, the number of poles of the rotor 9 is 10.

The permanent magnet 95 is a rare earth magnet capable of obtaining a high magnetic force, but the rare earth magnet contains Dy (dysprosium) or the like, and therefore, costs are incurred in materials. Further, the permanent magnet 95 is formed by cutting a block-shaped magnet material, and therefore, the processing cost is also consumed. The non-commutated pole type rotor 9 has the same number of permanent magnets 95 as the number of poles, and thus, the manufacturing cost is high.

On the other hand, the rotor 5 of embodiment 1 is of a commutating pole type, and has a magnet pole P1 and a virtual pole P2 as described with reference to fig. 3. The number of permanent magnets 55 can be halved as compared with the rotor 9 of the comparative example having the same number of poles, and therefore, the manufacturing cost of the rotor 5 can be greatly reduced.

On the other hand, the commutating pole rotor 5 has a problem that the magnetic flux density distribution in the virtual magnetic pole P2 is likely to be shifted. That is, when the motor 2 is operated, the magnetic flux from the rotor 5 is linked with the coil 30 (fig. 1) of the stator 1, and an induced voltage is generated, thereby generating a driving force for rotating the rotor 5.

In both the poles P1, P2 of the rotor 5, the magnetic flux density distribution is preferably symmetrical about the pole center. However, since the permanent magnets 55 are not provided in the virtual magnetic poles P2, the magnetic flux density distribution tends to shift to one side in the circumferential direction by the magnetic field generated by the current flowing through the coils 30 of the stator 1, that is, the stator magnetic field.

When the magnetic flux density distribution of the virtual magnetic pole P2 is shifted, the harmonic component of the induced voltage increases, and as a result, an iron loss called high-frequency iron loss occurs in the stator core 10 through which the magnetic flux of the rotor 5 flows. The core loss changes to heat energy in the stator core 10, and thus the temperature of the stator core 10 increases.

In embodiment 1, since the width W2 (fig. 5) of the tooth 12 of the 2 nd core portion 10B of the stator core 10 is narrower than the width W1 (fig. 4) of the tooth 12 of the 1 st core portion 10A, the coil 30 can be wound in close contact with the insulating portion 20 surrounding the tooth 12 as described above (fig. 8 a).

Therefore, heat generated in the stator core 10 can be dissipated via the coil 30, and a temperature rise of the stator core 10 can be suppressed. By suppressing the temperature rise of the stator core 10, the high-temperature demagnetization of the permanent magnet 55 can be suppressed, and as a result, stable operation of the motor 2 can be achieved.

A part of heat flowing from the stator core 10 to the coil 30 is radiated to the outside via the circuit board 45 and the lead 47 (fig. 1). Further, the other part of the heat flowing from the stator core 10 to the coil 30 flows to the heat radiating member 44 via the molded resin portion 4, and radiates the heat from the heat radiating member 44 to the outside.

Further, since a current flows through the coil 30, the temperature of the coil 30 increases due to copper loss. When the temperature of the coil 30 increases, heat is not easily transferred from the stator core 10 to the coil 30.

In embodiment 1, the coils 30 are wound in a line and are arranged in the slots 13 at a high density. Therefore, the duty ratio in the groove 13 becomes high, and by making the duty ratio high, the copper loss is reduced. Further, since the coil 30 is wound in a state of being closely adhered to the insulating portion 20, the circumference of the coil 30 may be short, and by shortening the circumference of the coil 30, copper loss is also reduced. As a result, the temperature rise of the coil 30 due to copper loss can be suppressed, and heat can be dissipated from the stator core 10 to the coil 30.

Further, since the coils 30 are wound in a regular arrangement, not only the coils 30 and the insulating portion 20 but also the coil wires of the coils 30 can be closely adhered to each other. Therefore, heat dissipation from the stator core 10 to the coil 30 can be promoted, and the effect of suppressing the temperature rise of the stator core 10 can be improved.

In addition, when the coil 30 is wound across the plurality of teeth 12, the gap between the coil 30 and the insulating portion 20 becomes large, but since the coil 30 is wound so that the salient poles are concentrated, the gap between the coil 30 and the insulating portion 20 is not easily generated. Therefore, heat dissipation from the stator core 10 to the coil 30 can be further promoted, and the effect of suppressing the temperature rise of the stator core 10 can be further improved.

Further, since the coil 30 is wound so that the short sides thereof are cross-wound, and the intersection a is located on the end face 12a of the tooth 12, the coil 30 can be arranged in the groove 13 at a high density, and the space factor can be improved. This allows the coil 30 and the insulating portion 20 to be more closely bonded to each other, and allows the coil wires of the coil 30 to be more closely bonded to each other. Further, by increasing the duty ratio, the copper loss of the coil 30 can be reduced. As a result, heat dissipation from the stator core 10 to the coil 30 can be further promoted.

Further, since the insulating film 22 is provided on the groove 13 side of the tooth 12, the interval between the tooth 12 and the coil 30 is narrowed, and heat is easily transferred from the tooth 12 to the coil 30 via the insulating film 22. Therefore, heat dissipation from the stator core 10 to the coil 30 can be further promoted.

Here, the 2 nd core portion 10B is provided at both axial end portions of the stator core 10, but the 2 nd core portion 10B may be provided at least one axial end portion of the stator core 10.

The magnet insertion hole 51 of the rotor core 50 is formed in a straight line in a direction perpendicular to the magnetic pole center line N1, but the magnet insertion hole 51 may be formed in a V-shape. Further, 2 or more permanent magnets 55 may be disposed in each of the magnet insertion holes 51.

As described above, the motor 2 is an IPM motor in which the permanent magnets 55 are disposed in the magnet insertion holes 51 of the rotor core 50, but may be an SPM (surface magnet) motor in which the permanent magnets 55 are disposed on the surface of the rotor core 50.

< effects of embodiments >

As described above, the motor 2 of embodiment 1 includes the commutated pole rotor 5 and the stator 1, and the stator core 10 of the stator 1 includes the 1 st core portion 10A located at the axial center and the 2 nd core portion 10B located at the axial end, and the area of the slot 13 in the 1 st core portion 10A is larger than the area of the slot 13 in the 2 nd core portion 10B. Therefore, the coil 30 can be wound in close contact with the insulating portion 20 surrounding the teeth 12, and heat of the stator core 10 can be dissipated through the coil 30. As a result, the temperature rise of the stator core 10 can be suppressed.

In particular, since the coils 30 are wound in order, concentrated salient pole winding, and short side cross winding, the coils 30 and the teeth 12 can be closely attached to each other via the insulating portion 20, and the coils 30 can be arranged in the slots 13 at a high density. As a result, heat of the stator core 10 can be efficiently dissipated from the coil 30, and the effect of suppressing the temperature rise of the stator core 10 can be improved.

Embodiment 2

Next, embodiment 2 will be described. Fig. 14 is a cross-sectional view showing stator 8 of embodiment 2. The stator core 80 of the stator 8 includes an annular yoke 81 centered on the axis Ax, and a plurality of teeth 82 protruding radially inward from the yoke 81. Slots 83 for receiving the coils 30 are formed between adjacent teeth 82.

The stator core 80 of embodiment 2 is divided into a plurality of divided cores 80A each including 1 tooth 82. Here, the number of split cores 80A is 12. The split core 80A is split by a split surface 85 formed on the yoke 81. With this configuration, the stator core 80 can be linearly expanded.

Each of the split cores 80A is obtained by laminating a plurality of laminated elements and fixing the laminated elements by caulking, welding, bonding, or the like. Here, the split cores 80A are formed with 3 caulking portions 87, 88, the caulking portion 87 is formed in the yoke 81, and the caulking portion 88 is formed in the teeth 82. However, the number and arrangement of the caulking portions are arbitrary.

Fig. 15 (a) is a diagram showing a state in which the stator core 80 is linearly expanded. In the example shown in fig. 15 (a), adjacent divided cores 80A are connected to each other by a connecting portion 86 provided on the outer peripheral side of the dividing surface 85. The connecting portion 86 is a thin portion or a caulking portion that can be plastically deformed.

In forming the stator 8, the insulator 21 (fig. 6B) and the insulating film 22 (fig. 6C) are attached to each of the split cores 80A in a state where the stator cores 80 are linearly spread, and the coil 30 is wound around the teeth 82 with the insulator interposed therebetween.

Since the stator core 80 is linearly extended, the winding nozzle used for winding can be relatively freely moved without interfering with the stator core 80, and the coil 30 can be wound at a higher density.

After winding the coil 30 around the teeth 82 of each of the split cores 80A, the stator core 80 is bent into a ring shape, and both ends of the stator core 80 are welded to each other, thereby obtaining the stator 8 shown in fig. 14.

Fig. 15 (B) is a diagram showing another example of the stator core 80. In the example shown in fig. 15 (B), the split cores 80A constituting the stator core 80 are not connected to each other. The split cores 80A are welded to each other at the split surfaces 85 and integrated.

In this case, the insulator 21 (fig. 6B) and the insulating film 22 (fig. 6C) are also attached to each of the split cores 80A, and the coil 30 is wound around the teeth 82 with the insulator 21 interposed therebetween. Then, the divided cores 80A are welded to each other at the dividing surface 85, whereby the stator 8 shown in fig. 14 is obtained.

Except for the above, the motor of embodiment 2 is configured in the same manner as the motor 2 of embodiment 1.

In embodiment 2, since the stator core 80 is configured by combining a plurality of split cores 80A, the coils 30 can be wound on the teeth 82 of the split cores 80A with high density. Therefore, the coil 30 and the insulating portion 20 can be closely attached, and the coil wires of the coil 30 can be closely attached to each other, so that heat of the stator core 10 can be efficiently dissipated from the coil 30. As a result, the effect of suppressing the temperature rise of the stator core 10 can be further improved.

< air conditioner >

Next, an air conditioner to which the motor according to each of the above embodiments can be applied will be described. Fig. 16 (a) is a diagram showing a configuration of an air conditioner 500 to which the motor 2 of embodiment 1 is applied. The air conditioner 500 includes an outdoor unit 501 and an indoor unit 502. The outdoor unit 501 and the indoor unit 502 are connected by a refrigerant pipe 503.

The outdoor unit 501 includes, for example, an outdoor fan 510 as a propeller fan, and the indoor unit 502 includes, for example, an indoor fan 520 as a cross-flow fan. The outdoor blower 510 has an impeller 511 and a motor 2A for driving the same. The indoor fan 520 has an impeller 521 and a motor 2B for driving the impeller. The motors 2A and 2B are each constituted by the motor 2 described in embodiment 1. Fig. 16 (a) also shows a compressor 504 for compressing the refrigerant.

Fig. 16 (B) is a cross-sectional view of the outdoor unit 501. The motor 2 is supported by a frame 509 disposed in a casing 508 of the outdoor unit 501. An impeller 511 is mounted on the shaft 6 of the motor 2 via a hub 512.

In the outdoor fan 510, the impeller 511 is rotated by the motor 2A to blow air out of the room. During cooling operation of the air conditioner 500, heat released when the refrigerant compressed by the compressor 504 is condensed in a condenser (not shown) is released outdoors by the air blown by the outdoor fan 510.

In the indoor fan 520 (fig. 16 (a)), the impeller 521 is rotated by the motor 2B to send air into the room. During cooling operation of the air conditioner 500, air, which takes heat when the refrigerant evaporates in an evaporator (not shown), is blown into the room by the air blowing of the indoor fan 520.

Since the motors 2A and 2B are configured by the motor 2 according to embodiment 1, stable operation can be performed by suppressing the temperature rise of the stator core 10. Accordingly, the reliability of the operation of the outdoor blower 510 and the indoor blower 520 can be improved.

The motors 2A and 2B are not limited to the motor 2 of embodiment 1, and may be the motor of embodiment 2. The motors of the embodiments are used for both the outdoor fan 510 and the indoor fan 520, but may be used for only one of them.

The motor 2 described in each embodiment is not limited to the blower, and may be used for a compressor of an air conditioner, and may be used for electric devices other than an air conditioner, for example, household electric devices, ventilator, machine tool, and the like.

While the preferred embodiments have been described above in detail, various modifications and variations can be made to these embodiments.

Description of the reference numerals

1: a stator; 2. 2A, 2B: a motor; 3: molding the stator; 4: molding a resin portion; 5: a rotor; 6: a shaft; 8: a stator; 9: a rotor; 10: a stator core; 10A: a1 st iron core part; 10B: a2 nd core portion; 11: a yoke; 11a: an outer periphery; 11b: an inner periphery; 11c: an inner periphery; 12: teeth; 12a: an end face; 12b: a side surface; 12c: a side surface; 12e: a tooth top; 12f: an opposing face; 12g: an opposing face; 13: a groove; 20: an insulating part; 21: an insulator; 22: an insulating film; 30: a coil; 31. 32, 33: a coil wire; 44: a heat radiating member; 45: a circuit substrate; 50: a rotor core; 51: a magnet insertion hole; 55: a permanent magnet; 80: a stator core; 80A: dividing the iron core; 81: a yoke; 82: teeth; 83: a groove; 85: a dividing surface; 86: a connecting part; 500: an air conditioning device; 501: an outdoor unit; 502: an indoor unit; 504: a compressor; 510: an outdoor blower; 511: an impeller; 520: an indoor blower; 521: an impeller; a: an intersection; p1: a magnet pole; p2: virtual magnetic poles.

Claims (13)

1. An electric motor, wherein the electric motor has:

a rotor having an annular rotor core centered on an axis and a permanent magnet attached to the rotor core, the permanent magnet constituting a magnet pole, a part of the rotor core constituting a virtual pole; and

a stator having a stator core surrounding the rotor core from a radial outer side centering on the axis and a coil wound around the stator core,

the stator core has slots for receiving the coils,

the stator core has a1 st core portion located at the center in the direction of the axis of the stator core and a2 nd core portion located at the end in the direction of the axis of the stator core,

the area of the groove in the 2 nd core portion is larger than the area of the groove in the 1 st core portion.

2. The motor according to claim 1, wherein,

the stator core has teeth adjacent to the slots in a circumferential direction centered on the axis,

the width of the tooth in the 1 st core portion in the circumferential direction is wider than the width of the tooth in the 2 nd core portion in the circumferential direction.

3. The motor according to claim 2, wherein,

an insulating portion is provided between the stator core and the coil,

the insulating portion is engaged with a stepped portion formed in the portion of the tooth where the width varies.

4. The motor according to claim 2 or 3, wherein,

the coils are wound around the teeth of the stator core in a orderly wound manner.

5. The motor according to any one of claims 2 to 4, wherein,

the coil is wound around the teeth of the stator core in such a manner that salient poles are intensively wound.

6. The motor according to any one of claims 2 to 5, wherein,

the coil is wound around the stator core in a manner of constituting a plurality of layers,

on one end face in the direction of the axis of the tooth, coil lines of mutually different layers of the coil intersect.

7. The motor according to any one of claims 1 to 6, wherein,

inside the slot, a coil wire constituting the coil extends parallel to the axis.

8. The motor according to any one of claims 1 to 7, wherein,

an insulating film is provided on the slot-side surface of the stator core.

9. The motor according to any one of claims 1 to 8, wherein,

the stator core is configured by combining a plurality of divided cores each including 1 tooth in a circumferential direction around the axis.

10. The motor according to any one of claims 1 to 9, wherein,

the motor also has a molded resin portion surrounding the stator.

11. The motor according to claim 10, wherein,

the motor further has a circuit substrate connected to the coil and covered with the molded resin portion.

12. A blower, wherein the blower has:

the motor of any one of claims 1 to 11; and

an impeller rotated by the motor.

13. An air conditioning apparatus, wherein,

the air conditioner has an outdoor unit and an indoor unit,

at least one of the outdoor unit and the indoor unit has the blower according to claim 12.